"Making aliyah" means "going to the Land of Israel." In the Talmud and the Bible, travel to the Land of Israel is always referred to as "going up" since it is a holier place. In today's speech, "making aliyah" has come to mean actually moving to the Land and becoming a citizen here.

Hence in Modern Hebrew "going down" refers to someone who leaves Israel to live elsewhere.

The story is told of an Israeli in difficult financial straits who thinks he might do better in the US. When he announces his plans to go to Los Angeles, all his friends ask, "Are you going down?'" "No! No!" he replies, "I'm just going there to make some money. Then I'll come back to Israel."

In LA he gets a job as an elevator operator. The first day on the job, he rides the elevator up to the tenth floor, opens the door, and a bunch of people cram in. "Going down?" he asks. "No! No!" they reply, "We're just here to make some money. Then we'll go back to Israel."